| Sorting accuracy | Check how consistently the sorter removes specified defects while retaining acceptable beans. Results depend on the sample, defect definitions, feed conditions, and machine settings. | Test the actual defect mix, such as discolored, insect-damaged, broken, or foreign-material pieces. | Test the intended roast profile and identify the color defects that matter, such as scorched, under-roasted, or unusually pale beans. | Run a representative sample and separately inspect the accepted and rejected streams. Record defect removal and good-bean loss; do not rely on a quoted accuracy figure without its test conditions. |
| Throughput | Compare sustained processing capacity in kilograms per hour at the required sorting quality, not just the machine’s maximum or nominal rate. | Bean size, moisture, feed uniformity, and defect load can affect the rate. | Bean size, roast level, surface oil, breakage, and the required separation quality can affect the rate. | Ask for a timed trial using your coffee and target settings. Record feed rate, accepted output, rejected output, and any recirculation needed. |
| Coffee compatibility | Confirm the feed system, chutes, optical setup, and product-contact parts suit the coffee being processed. | Verify performance across the planned origins, screen sizes, and moisture range. | Check gentle handling and reliable feeding. Roasted beans are more brittle; oily dark roasts may require more frequent cleaning. | Test each coffee type that will run on the line, including the lightest and darkest planned lots. Check for bridging, bouncing, breakage, and residue buildup. |
| Detection capability | Match the optical system to the defects to be removed. Color sorting is suited to visible color differences; shape or additional sensing options may help with other defect types. | Assess whether the system can distinguish target defects from natural bean-color variation. | Assess whether the system can distinguish roast defects without rejecting acceptable variation in roast color. | Ask the supplier to demonstrate each important defect using your sample. Confirm which defects the selected sensor can and cannot detect. |
| Feed and separation stability | Look for an even, single-layer presentation to the cameras and reliable separation into accepted and rejected streams. | Check that beans feed consistently without overlapping or surging. | Check that fragile beans are handled smoothly and that light fragments do not disrupt separation. | Observe operation at both the intended rate and a reduced rate. Check for uneven distribution, blockages, and unintended good-bean rejection. |
| Recipe setup and changeover | Evaluate how easily settings can be created, saved, and repeated for different lots or product types. | Confirm recipes can accommodate changes in origin, screen size, and incoming defect profile. | Confirm recipes can accommodate changes in roast level and bean appearance. | Time a changeover between two representative coffees and verify that the saved settings reproduce the agreed test result. |
| Cleaning and maintenance | Review access to lenses, chutes, ejectors, and other areas that require routine inspection or cleaning. | Check dust control and the cleaning steps needed between lots. | Check how easily oily residue and coffee fragments can be removed, especially when processing darker roasts. | Request the cleaning schedule, routine maintenance list, and expected downtime. Confirm that cleaning can be performed safely and consistently. |
| Final selection | Choose based on verified performance on your own coffee, required output, operating conditions, and service needs. | Prioritize demonstrated defect removal and stable capacity for the green-bean range you handle. | Prioritize gentle handling, reliable color discrimination, and practical cleaning for your roast range. | Compare shortlisted machines using the same sample, defect definitions, target rate, and acceptance criteria. Request the test results in writing. |